[profiler] Add extra CHECK to catch a crash in profiler.

src/profiler/profile-generator.cc

Index: src/profiler/profile-generator.cc
diff --git a/src/profiler/profile-generator.cc b/src/profiler/profile-generator.cc
index a4da7cae7f320400aa366a5084c497674ee45e35..81ad47f9adc2854b8695dc1a6be725f77228b12f 100644
--- a/src/profiler/profile-generator.cc
+++ b/src/profiler/profile-generator.cc
@@ -764,6 +764,7 @@ CodeEntry* ProfileGenerator::FindEntry(void* address) {
     if (start <= address && address < end) {
       RuntimeCallCounter* counter =
           reinterpret_cast<RuntimeCallCounter*>(address);
+      CHECK(counter->name);
       entry = new CodeEntry(CodeEventListener::FUNCTION_TAG, counter->name,
                             CodeEntry::kEmptyNamePrefix, "native V8Runtime");
       code_map_.AddCode(reinterpret_cast<Address>(address), entry, 1);